Electrolysis, as an alternative way for hydrogen production using flow meters
In this blog I will highlight an application using both a thermal- and Coriolis mass flow controller. An application for a customer in the field of Renewables & Environment showing us an alternative way to split water for hydrogen production.
Hydrogen production is a multi billion dollar industry worldwide of which the major part is consumed on-site in oil refining and in the production of ammonia and to convert heavy petroleum sources into lighter fraction suitable for use as fuels. The most known technogies used here are steam reforming, electrolysis and thermolysis. About 95% of the hydrogen produced is from using fossil fuels.
Steam reforming technology
The overwhelming majority of hydrogen is generated in a chemical way, through the reaction of hydrocarbons such as natural gas with steam at high temperatures, the so-called steam reforming technology. In this process, hydrogen is released from the natural gas with the greenhouse gas carbon dioxide as a by-product
Solar thermal energy and electricity is the most common way to produce renewable clean hydrogen. Another, novel way to generate hydrogen is using water splitting. This is a chemical reaction in which water is separated into oxygen and hydrogen. Various techniques of water splitting can be used and are already patented, such as splitting water electrochemically. A more alternative way to split water into hydrogen and oxygen is using electrolysis and other physical processes. Both gases have to be separated from each other with a membrane, to obtain hydrogen as pure as possible.
Using mass flow controllers for water splitting
To effectuate the electrolysis process properly, mass flow controllers can be used. How does this work?
As part of the process, the performance of the membrane that separates hydrogen from oxygen has to be measured. To that end, both hydrogen and oxygen have to be supplied to the membrane in known amounts in an accurate way, and the flows that leave the membrane also have to be measured accurately.
For a German customer in the field of Renewables & Environment, Bronkhorst provided an experimental setup consisting of a Coriolis mass flow controller to control the oxygen and a thermal mass flow controller for hydrogen. In this way, hydrogen and oxygen are fed to the membrane in a controlled way.
The permeate - that is the part of the feed that passes the membrane - enters a three way valve where a choice can be made to measure the flow rate or the composition of the permeate gas flow. The flow rate is measured using another thermal device, and the gas composition by means of a binary gas sensor. This sensor can only handle a specific mass flow. To measure the mass flow of the retentate – part of the feed that is retained by the membrane - a second Coriolis instrument can be used.
For more information about this application, please download our application note.
Or download our white paper with in-depth information about our thermal mass flow meters/controllers.